June 1 marks the official start of the Atlantic Hurricane Season, which continues through November 30. In an average season, based on data from 1981 to 2010, 12 named tropical cyclones should be expected, with 6 of these reaching hurricane intensity, and 3 developing into major hurricanes.

“This outlook is a general guide to the expected overall activity during the upcoming hurricane season,” the National Weather Service (NWS) Climate Prediction Center says. “It is not a seasonal hurricane landfall forecast, and it does not predict levels of activity for any particular location.”

The official NOAA 2017 Atlantic hurricane season outlook indicates a 45% probability of an above-normal season, a 35% probability of a near-normal season, and a 20% probability of a below-normal season. This outlook calls for between 11 and 17 named storms. This already includes the pre-season Tropical Storm Arlene, which occurred in April. Of these named storms, between five and nine of them could reach hurricane intensity, with between two and four of these becoming major hurricanes — Category 3 or above.